Has the ThinPrep method of cervical screening maintained its improvement over conventional smears in terms of specimen adequacy?

Can LBC Completely Replace Conventional Pap Smear in Developing Countries

Background

A number of screening techniques have been developed to reduce the incidence of cervical cancer, most common of which is conventional Pap smear (CPS) being overtaken by liquid-based cytology (LBC) in most of the developed countries. There are a number of studies with conflicting results, and no method has been shown superior in terms of all parameters. LBC was introduced in our hospital in 2014, and we planned to do a study and compare results of the two techniques. This study aims to compare the two methods in terms of sensitivity, specificity, positive predictive value and negative predictive value, turnover time, cost-effectiveness, sample adequacy. This study has been done in 100 women with unhealthy cervix to increase the output.

Method

This was a prospective observational study. A total of 100 women fulfilling the inclusion criteria were subjected to screening test. In first 50 cases, first conventional Pap smear was taken and then LBC, and in remaining 50 cases, first LBC and then conventional Pap smear were taken; this was done to remove bias.

Results

The number of unsatisfactory slides was reduced with LBC, and turnover time was less for LBC. The detection of ASCUS was increased with LBC, but the detection of higher-grade lesions (HSIL and SCC) was equal with both tests.

Conclusion

The superiority of LBC with respect to reduction in the number of unsatisfactory slides and less turnover time is being offset with increased detection of low-grade lesions subjecting women to further testing increasing the cost of programme and anxiety among women. It is difficult to say that it can completely replace conventional Pap smear in low-resource settings.

A comparison of liquid-based cytology with conventional Papanicolaou smears in cervical dysplasia diagnosis

Background:

Due to the high number of women affected by cervical cancer and the importance of an early diagnosis, combined with the frequent incidence of false-negative Papanicolaou (Pap) smear screening results for this disease, several studies have been conducted in recent years in order to find better tests. Liquid-based cytology (LBC) tests, including the liquid-based thin layer method, have demonstrated the highest potential for reducing false-negative cases and improved sample quality. This study aimed to compare the strength of the Pap smear test with fluid cytology and conventional tests in detecting cervical dysplasia.

Materials and Methods:

This descriptive-analytic study was conducted on 366 women who attended private laboratories for a Pap smear. The Pap smear sampling was conducted simultaneously using two methods: conventional Pap (CP) smear and LBC), from the cervix.

Results:

The mean age of the participants was 32 ± 8.8 years. Diagnostic results of endocervical cells, epithelial cells, vaginitis cells, and metaplastia were consistent with both conventional and liquid cytology smears, and the kappa coefficient was determined to be significant (P < 0.001). In total, 40.5% of diagnostic cases indicated bacterial inflammation 80.3% of the diagnoses in both methods were P1 and 3.9% of cases diagnosed were P2, the overall diagnostic consistency was 83.9% between the two sampling methods. The inflammation diagnosis was 40.5% and this was consistent in both methods of LBC and CP. There was one case of a false-negative diagnosis in the LBC method and 14 cases in the CP method.

Conclusion:

Results showed that the LBC may improve the sample's quality and reduce the number of unsatisfactory cases more than with the CP method.

Common causes for unsatisfactory Pap tests in a high-risk population: insights into a yet unresolved problem in gynecologic cytology

INTRODUCTION

Although the rates are generally low (0.2%-10%), unsatisfactory Papanicolaou (Pap) tests are associated with an increased risk of epithelial lesions on subsequent follow-up. Therefore, some studies have recommended extra laboratory processing, resampling of patients, and more recently, human papillomavirus testing.

MATERIALS AND METHODS

Consecutive cases signed out as unsatisfactory for evaluation (UE) were identified from January 1, 2008 to December 31, 2010 in the cytology laboratory at Houston Methodist Hospital. Patient's demographics, relevant prior clinical history, type of Pap test, reasons for UE diagnosis, and cytology or histology follow-up were obtained from the pathology database.

RESULTS

Among 56,563 total Pap tests, 276 were signed out as UE (0.47%). Nearly half of these patients were older than 50 years (15 to 88 years). The majority (85%) of patients over 50 years old had a history of prior gynecologic cancer. Low squamous cellularity was the most common cause of UE in all age groups. Follow-up abnormalities were identified in 21 of 73 patients (29%).

CONCLUSIONS

Low squamous cellularity was the most common cause of UE and was often seen in women older than 50 years of age. The significant risk associated with UE emphasizes the importance of appropriate follow-up on these patients.

Gynecologic cytology on conventional and liquid-based preparations: a comprehensive review of similarities and differences

Liquid-based preparations (LBPs) have largely replaced conventional Papanicolaou smears (CPS) for cervical samples in the United States and in many other industrialized countries. The two FDA-approved LBP currently in use include ThinPrep (TP), (Hologic Inc., Bedford, MA) and SurePath (SP), (BD Diagnostic, Burlington, NC). Split-sample and direct-to-vial studies have shown that LBPs show an overall improvement in sample collection and processing, reduce artifacts that interfere in diagnosis, are more sensitive, can be utilized for ancillary tests and are a cost-effective replacement for CPS. Comparative analyses of diagnostic accuracy indicate that LBPs perform at least as well as CPS. However, the added advantages of standardized, automated preparations and screening, reduced unsatisfactory rate, improved specimen adequacy and ability to perform human papillomavirus (HPV) test, are enough to continue use of LBP. The cytologic features in LBP are similar to CPS with subtle differences, particularly in background information. There are also subtle differences between the two LBPs, SP and TP, which are reflective of different sampling devices, collection media, and processing techniques. Architecturally, LBP shows smaller cell clusters and sheets and more dyscohesion. Cytologically, enhanced nuclear features and smaller cell size are more prominent. Advances in liquid-based Papanicolaou's (Pap) test have lead to well-defined patient management guidelines by the American Society for Colposcopy and Cervical Pathology. Herein, we review these aspects of Pap test including, morphology, automation, ancillary tests (HPV and immunochemistry), pertinent QA/QC monitors, patient management guidelines, and review of pertinent literature.

Unsatisfactory rates vary between cervical cytology samples prepared using ThinPrep and SurePath platforms: a review and meta-analysis

OBJECTIVE

To compare unsatisfactory rates between the two major liquid-based cytology (LBC) platforms, namely ThinPrep (Hologic) and SurePath (Becton Dickinson).

DESIGN

The authors performed both a systematic review and a meta-analysis. Inclusion criteria were English language, data presented on unsatisfactory rates for either ThinPrep or SurePath, utilising actual patient samples (ie, not laboratory manipulated samples) and no manipulation using acetic acid to increase the satisfactory rate. The authors searched PubMed for articles using the keywords 'SurePath' or 'ThinPrep' and 'unsatisfactory'. References of retrieved studies were searched for additional articles. Key researchers in the field were also contacted.

PARTICIPANTS AND INTERVENTIONS

Eligible studies were reviewed for rates of unsatisfactory cervical cytology smears processed on either the ThinPrep or SurePath platforms (compared with a general linear model) or data on unsatisfactory rates for both platforms for the same laboratory and the same patient population (compared with a meta-analysis using a random effects model and pooled RR).

PRIMARY OUTCOME MEASURE

Unsatisfactory rate of cervical cytology smears.

RESULTS

A total of 1 120 418 cervical cytology smears were reported in 14 different studies using the SurePath platform for an overall unsatisfactory rate (weighted average) of 0.3%. 28 studies reported on 1 148 755 smears prepared using the ThinPrep platform for an overall unsatisfactory rate (weighted average) of 1.3%. The general linear model did not show a difference between LBC platforms when other variables were controlled for; however, the power to detect a difference (0.087) was very low. The meta-analysis performed on four studies where both ThinPrep and SurePath results were reported from the same laboratory showed fewer unsatisfactory tests from the SurePath platform (RR 0.44, 95% CI 0.25 to 0.77, p=0.004).

CONCLUSIONS

Multiple factors affect LBC unsatisfactory rates. In a meta-analysis, cervical cytology samples prepared on the SurePath platform show significantly fewer unsatisfactory smears than those prepared on the ThinPrep platform.